Modified textiles and other materials and methods for their preparation

ABSTRACT

Provided are compounds and methods for modifying a material to change properties of the material, as well as a variety of products obtained using the methods. In one embodiment, a material comprising one or more modifiable functional groups is reacted with an activated hydrophobic acyl group in the presence of a hindered base, thereby to covalently attach the hydrophobic acyl group to the modifiable functional groups on the material. The material which is modified may be, for example, a carbohydrate, and the modifiable functional groups on the material may be hydroxyls. For example, materials such as cellulose may be modified by reacting it with an acid chloride or acid anhydride including a hydrophobic acyl group, in the presence of a hindered base, such as tripentylamine, to attach the hydrophobic acyl groups to the hydroxyls on the cellulose, thereby to increase the hydrophobicity of the cellulose. The methods and compounds disclosed herein may be used to modify materials to improve properties such as resistance, grease repellency, soil resistance and permanent press properties.

This is a divisional of application Ser. No. 09/586,185, filed on Jun.1, 2000, now U.S. Pat. No. 6,485,530, which is a divisional ofapplication Ser. No. 09/274,751, filed on Mar. 23, 1999, now abandoned,which claims the benefit of U.S. Provisional patent applications SerialNo. 60/080,185, filed Mar. 24, 1998, Ser. No. 60/093,820, filed Jul. 23,1998, Ser. No. 60/093,911, filed Jul. 23, 1998; Ser. No. 60/105,890,filed Oct. 27, 1998, and Ser. No. 60/117,641, filed Jan. 28, 1999; thedisclosures of each of which are incorporated herein by reference intheir entirety.

TECHNICAL FIELD

This invention relates generally to methods for the modification oftextile and other materials, for example by the attachment ofhydrophobic moieties, to impart properties thereon such as waterrepellency and permanent press.

BACKGROUND ART

Most chemical research in the textile field was conducted in the 1950s,60s, and 70s. This work has been extensively reviewed. For example, see:Smith and Block, Textiles in Perspective, Prentice-Hall, EnglewoodCliffs, N.J., 1982; Handbook of Fiber Science and Technology, MarcelDekker, New York, N.Y., Vols. I-III, 1984; S. Adanur, Wellington SearsHandbook of Industrial Textiles, Technomic Publishing Company, Inc.,Lancaster, Pa., 1995; and Philip E. Slade, Handbook of Fiber FinishTechnology, Marcel Dekker, New York, 1998). A large majority of thispublished research was never commercialized due to inhibitory costs orthe impracticality of integration into textile production processes.There has been less research in this area in recent years. Most currentwork is centered on optimizing existing technology to reduce costs andcomply with recent government regulations.

Methods have been developed in the art for making textile materialswater repellent. The terms “water repellent” and “waterproof” aredistinguishable as related to textiles. Water repellent fabricsgenerally have open pores and are, permeable to air and water vapor.Waterproofing involves filling the pores in the fabric with a substanceimpermeable to water, and usually to air as well. For the purpose ofeveryday clothing, water repellent fabric is preferable because of thecomfort afforded by the breathability of the clothing.

Current commercial processes for producing water repellent fabrics arebased on laminating processes (C. J. Painter, Journal of Coated Fabrics,26:107-130 (1996)) and polysiloxane coatings (Philip E. Slade, Handbookof Fiber Science and Technology, Marcel Dekker, New York, N.Y., Vol. II,1984, pp. 168-171). The laminating process involves adhering a layer ofpolymeric material, such as Teflon®, that has been stretched to producemicropores, to a fabric. Though this process produces durable, waterrepellent films, it suffers from many disadvantages. The application ofthese laminants requires special equipment and therefore cannot beapplied using existing textile processes. Production of the film iscostly and garments with this modification are significantly moreexpensive than their unmodified counterparts. The colors and shades ofthis clothing can be limited by the coating laminate film color orreflectance. Finally, clothing made from this material tends to beheavier and stiffer than the untreated fabric. This material also can bedisadvantageous due to mismatched expansion and shrinkage properties ofthe laminate. Polysiloxane films suffer from low durability tolaundering which tends to swell the fabric and rupture the siliconefilm.

Methods of imparting hydrophobic character to cotton fabric have beendeveloped including the use of hydrophobic polymer films and theattachment of hydrophobic monomers via physi- or chemisorptiveprocesses. Repellents used based on monomeric hydrocarbon hydrophobesinclude aluminum and zirconium soaps, waxes and waxlike substances,metal complexes, pyridinium compounds, methylol compounds, and otherfiber reactive water repellents.

One of the earliest water repellents was made by non-covalently applyingwater soluble soap to fiber and precipitating it with an aluminum salt.J. Text. Res. 42:691 (1951). However, these coatings dissolve inalkaline detergent solution, therefore washfastness is poor. Zirconiumsoaps are less soluble in detergent solutions (Molliet, Waterproofingand Water-Repellency, Elsevier Publ. Co., Amsterdam, 1963, p. 188);however, due to the non-covalent attachment to the fabric, abrasionresistance and wash fastness are poor. Fabric also has been made waterrepellent by coating it with a hydrophobic substance, such as paraffin.Text. Inst. Ind. 4:255 (1966). Paraffin emulsions for coating fabricsare available, for example, Freepel® (BF Goodrich Textile ChemicalsInc., Charlotte, N.C.). Waxes are not stable to laundering or drycleaning. Durability is poor due to non-covalent coating of the fabricand breathability is low.

Quilon chrome complexes polymerize to form —Cr—O—Cr— linkages (R. J.Pavlin, Tappi, 36:107 (1953)). Simultaneously, the complex formscovalent bonds with the surface of fibers to produce a water repellentsemi-durable coating. Quilon solutions require acidic conditions toreact thus causing degradation of the fiber through cellulosehydrolysis. Fabric colors are limited by the blue-green colorationimparted by the complex.

Pyridinium-type water repellents have been reviewed by Harding (Harding,J Text. Res., 42:691 (1951)). For example, an alkyl quaternary ammoniumcompound is reacted with cellulose at elevated temperatures to form adurable water-repellent finish on cotton (British Patent No. 466,817).It was later found that the reaction was restricted to the surface ofthe fibers (Schuglen et al., Text. Res. J., 22:424 (1962)) and the highcure temperature weakened the fabric. Pyridine liberated during thereaction has an unpleasant odor and the fabric had to be scoured afterthe cure. The toxicological properties of pyridine ended its use in the1970s when government regulations on such substances increased.

Methylol chemistry has been extensively commercialized in thecrosslinking of cellulose for durable press fabrics. N-methylolcompounds are prepared by reaction of an amine or amide withformaldehyde. Alkyl-N-methylol compounds can be reacted at elevatedtemperatures in the presence of an acidic catalyst with the hydroxylgroups of cellulose to impart durable hydrophobic qualities to cotton.British Patent Nos. 463,300 (1937) and 679,811 (1952). The reaction withcellulose is accompanied by formation of non-covalently linked (i.e.,non-durable) resinous material, thus decreasing efficiency. In addition,the high temperature and acid catalyst reduces the strength of thefabric. Recently, the commercial use of methylol compounds has beendecreasing due to concerns of toxic formaldehyde release from fabricstreated in such a manner.

Long-chain isocyanates have been used to hydrophobically modify cotton.British Patent No. 461,179 (1937); Hamalainen, et al., Am. Dyest. Rep.,43:453 (1954); and British Patent No. 474,403 (1937)). The high toxicityof isocyanates and significant side reactions with water, however,precluded it from commercial use. To, circumvent the water sensitivityof isocyanates, alkyl isocyanates were reacted with ethylenimine toyield the less reactive aziridinyl compound which was subsequentlyreacted with cellulose. German Patent No. 731,667 (1943); and BritishPatent No. 795,380 (1958). Though the toxicity of the aziridinylcompound was reduced compared to the isocyanate, the procedure stillrequired the handling of toxic isocyanate precursors. Also, the highcure temperature weakened the cellulose and crosslinkers were needed toincrease structural stability. Alkyl epoxides have been reacted withcellulose under acidic or basic conditions to produce water repellentcotton. German Patent No. 874,289 (1953). Epoxides are, in generalhowever, not very reactive and require long reaction times at hightemperatures and therefore have not been extensively commercialized.

Acylation of cotton with isopropenyl stearate from an acidic solution ofbenzene and curing was used to produce a hydrophobic coating for cotton.U.S. Pat. No. 4,152,115. The high cure temperature and acid catalysthowever weakens the cotton. This method disadvantageously usescarcinogenic and flammable solvents. The practicality of using flammablesolvents in fabric finishings is limited. Alkyl vinyl sulfones have beenreacted with cellulose in the presence of alkali to form a waterrepellent finish. U.S. Pat. No. 2,670,265. However, this method has notbeen commercialized because the alkali is not compatible withcross-linking reactants required for permanent press treatments.

Methods have been developed for imparting grease repellent properties tomaterials such as cotton. Perfluoroalkanoic acids have been applied in avariety of ways including as chromium complexes and as quaternaryamines. U.S. Pat. No. 2,662,835; Phillips et al., Text. Res. J., 27:369(1957); Tripp et al., Text. Res. J., 27:340 (1957); and Segal et al.,Text. Res. J., 28:233 (1958). Since these finishes are non-covalentlylinked to the fabric, they are not durable to laundering. Attempts weremade to covalently link fluorocarbons to cotton with perfluorinated acidchlorides in the presence of the base pyridine and dimethylformamidesolvent (Benerito et al., Text. Res. J., 30:393-399 (1960)), howeversignificant problems were encountered. The pyridine base formed aninsoluble complex with the acid chloride that could only be overcomewith the addition of large excesses of pyridine or the solventdimethylformamide. Also, the finish was readily subject to hydrolysisand not durable to laundering. Repellent finishes made by reaction ofglycidyl ethers of 1,1-dihydrofluoroalkanols with cellulose (Berni etal., Text. Res. J., 30:576-586 (1960)) produced a more durable finish,but required a reaction time of 30 h at 100° C. and were not extensivelycommercialized. Interest in monomeric fluorocarbon finishes has beensuperseded by the use of fluorinated polymer films.

Methods also have been developed for modifying cotton by crosslinking inorder to impart permanent press properties to the material. Thesemethods have been reviewed in: R. M. Rowell and R. A. Young, Eds.,Modified Cellulosics, Academic Press, New York, 1978; M. Levin and S.Sello, Eds., Handbook of Fiber Science and Technology, Vol. 2, Part A,Marcel Dekker, New York, 1984, pp. 1-318; and G. Hermanson, BioconjugateTechniques, Academic Press, San Diego, Calif., 1996, pp. 169-297. Thecovalent crosslinks prevent the cellulose chains from slipping, thusimparting high durable press characteristics. However, the short andstiff crosslinks cause the cotton structure to become brittle anddisplay poor tear strength. A variety of textile resins have beendeveloped to crosslink cellulose and impart durable-press properties,such as polymethylol compounds formed by the reaction of aldehydes withamines. They include melamineformaldehyde (British Patent Nos. 458,877,466,015 and 468,677), dimethylolethyleneurea (U.S. Pat. Nos. 2,416,046,2,416,057, 2,425,627, 2,436,311, 2,373,136, and 2,899,263; and BritishPatent Nos. 603,160 and 577,735), and urons/triazones (U.S. Pat. Nos.2,373,135; and 2,321,989; British Patent Nos. 575,260 and 845,468;German Patent No. 1,123,334; Angew. Chem., 60:267 (1948); Am. Dyest.Rep., 48:44 (1959); and Tex. Res J., 29:170 (1959).

Dimethyloldihydroxyethyleneurea (DMDHEU) has been used in the productionof durable-press garments. Text. Res. J., 51:601(1981). However, theDMDHEU system retains chlorine and causes yellowing and tendering of thecloth; therefore it is not suitable for use with white cloth. Resinshave been developed specifically for use with white cloth that areesters of carbamic acid (carbamates). U.S. Pat. Nos. 3,639,455, and4,156,784; Japanese Patent No. 599,505; British Patent Nos. 1,227,366,and 1,523,308; and French Patent Nos. 1,576,067 and 7,532,092. Thecrosslinking of the cellulose and polymerization of the resin generallyoccurs at the same time on the fabric. U.S. Pat. Nos. 5,447,537,4,975,209, 4,936,865, 4,820,307, and 3,995,998.

Methods for modifying materials with reactive groups such as hydroxylsand amines have been developed in the art, however, materials withhydroxyl groups, including polysaccharides such as cellulose, have beenfound to be difficult to covalently modify and therefore requirereactive modifiers or extreme conditions. Methods of reacting withhydroxyls that have been developed in the chemistry field include theuse of acid chlorides, anhydrides, succinimides, andcarbonyldiimidazole. See, e.g., J. March, “Advanced OrganicChemistry-Reactions, Mechanisms and Structure,”, 3rd Ed., John Wiley andSons, New York, 1995; and G. Hermanson, “Bioconjugate Techniques,”Academic Press, Inc., San Diego, 1996.

There is a need for methods for modifying various substrate materials,such as textile fibers of cotton or other cellulosic materials, wool,silk and other proteinaceous fibers, and various other natural, manmade, regenerated and synthetic fiber materials to alter and optimizetheir properties for use in different applications. There is a need formethods for improving the properties of cloth or fabric materialscontaining various natural, man made and/or synthetic fibers of varioustypes, in order to improve various performance properties such as waterresistance, soil resistance, speed of drying and permanent pressproperties. There further is a need for methods for producing modifiedtextile fiber materials and other substrates which may be used in a widerange of applications including clothing and apparel fabrics, andvarious items of apparel, socks, hosiery, fabrics for footwear, shoes,home furnishing, fabrics for upholstery and window treatments includingcurtains and draperies, and fabrics for outdoor furniture and equipment,as well as for industrial textile end uses.

DISCLOSURE OF THE INVENTION

Provided are methods of modifying various substrate materials to alterthe properties of the materials. In particular, compositions and methodsare provided that permit the modification of a variety of textile fibermaterials and similar substrates to alter properties including waterrepellency, grease repellency, soil resistance, oil or greaseresistance, permanent press, detergent free washing, increased speed ofdrying, and improving strength and abrasion resistance. The methods alsopermit improvement of comfort of fibers, wherein the fibers are usedalone or in combinations or blends with one or more others before orafter, treatment.

In one embodiment, provided are methods of modifying a material toincrease its hydrophobicity as well as a variety of products obtainedusing the methods. A material comprising one or more modifiablefunctional groups is reacted with an activated hydrophobic acyl group,such as an acid chloride or anhydride, in the presence of a hinderedbase, to covalently attach the hydrophobic acyl group to the modifiablefunctional groups on the material. The presence of the hindered baseadvantageously neutralizes unwanted side reactions by acids such as HClproduced during the reaction.

The material which is modified may comprise a carbohydrate, and themodifiable functional groups on the material may comprise hydroxyls.Cellulose in natural or regenerated form may be modified by reacting itwith an activated hydrophobic acyl group, such as an acid chloride oracid anhydride, in the presence of a hindered base, such astripentylamine, to attach the acyl groups to the hydroxyls on thecellulose, to increase the hydrophobicity of the cellulose.

Cellulose may be reacted with an activated acyl group, such as an acidchloride, RCOCl, or anhydride, (RCO)₂O, wherein R is a straight chainC8-C20 saturated hydrocarbon, for example a C10-C20 saturatedhydrocarbon. Exemplary acid chlorides include hexadecanoyl chloride andpolyethylene acid chlorides.

A cellulosic or other material may be reacted with an activated acylgroup such as an acid chloride, R(CH₂)₂COCl or anhydride, (R(CH₂)₂CO)₂O,wherein R is a C1-C10 fluorocarbon. For example, R may be CF₃—, orCF₃(CF₂)_(n)— wherein n is, for example, 1 to 10.

In a second step, the material may be further modified in a secondreaction with a small organic acid chloride, such as acetyl chloride, toacylate unreacted groups, such as hydroxyls, on the material.

A method of modifying a textile material also is provided comprisingreacting the material with an alkyl silane, thereby to covalently attachthe alkyl silane to the material. The alkyl silane has, for example, theformula RSiX₁X₂X₃, where R is a hydrocarbon or fluorocarbon, and one ormore of X₁, X₂, and X₃ are independently a halo or alkoxy group, and theremainder of X₁, X₂, and X₃ are independently alkyl. In one embodiment,X₁, X₂, and X₃ are independently chloro, ethoxy and methoxy, and theremainder of X₁, X₂, and X₃ are methyl. The material is, for example, acellulose or wool containing material.

Also is provided a method of modifying a textile material to increasethe hydrophobicity of the material, the method comprising crosslinkingthe material with hydrophobically modifieddimethyloldihydroxyethyleneurea. The textile material is, for example, acarbohydrate containing material and thedimethyloldihydroxy-ethyleneurea comprises, for example, a covalentlyattached hydrocarbon or fluorocarbon group.

Also provided is a method of modifying a cellulosic material, such as acotton material, the method comprising crosslinking the material with afunctionalized glucose molecule comprising a reactive group such as anisothiocyanate, isocyanate, acyl azide, sulfonyl chloride, aldehyde,glyoxal, oxirane, carbonated imidoester, carbodiimide, succinimideester, epoxide, alkyl halide, anhydride, acid chloride, or an activatedester.

The methods disclosed herein may be used to modify various substratematerials, such as textile fibers of cotton or other cellulosicmaterials, wool, silk and other proteinaceous fibers, and various othernatural, regenerated and synthetic fiber materials to alter and optimizetheir properties for use in different applications. Materials containingvarious natural, regenerated, man made and/or synthetic fibers in theform of cloth or fabric of various types may be modified, in order toimprove various performance properties such as water resistance, soilresistance, oil or grease resistance, speed of drying and permanentpress properties, such as smoothness or wrinkle resistance and “wash andwear”.

Materials comprising cellulose may be modified and are described by wayof example. A variety of other materials, such as other polysaccharidesor polyamines, also may be modified, for example, to improve theirhydrophobicity by the covalent attachment of hydrophobic groups.Cellulose containing materials which may be modified include cottonmaterials and various types of regenerated cellulose, such as rayon,including viscose rayon and lyocell, other natural cellulosics such aslinen; ramie and the like, in fiber, yarn or fabric form, which may beeither undyed or dyed prior to the reaction. Hydrophobic cellulosicmaterial can be made with selected covalently attached hydrophobicgroups to improve properties of the cellulosic substrate such as waterresistance and permanent press properties. Proteinaceous fibersincluding silk, wool, camel's hair, alpaca and other animal hairs andfurs and regenerated protein fibers may be modified, as well assynthetic fibers including polyamides, such as nylon 6 and 66, variouspolyesters, including polyethylene, glycol terephthalate and derivativesthereof and polytrimethylene terephthalate and other synthetic fiberswith suitable reactive properties. Various of these types of fibers alsocan be blended with one or more other fibers, before or after treatment,e.g. cotton or rayon and polyester, or wool and polyester, together, orwith silk, linen or rayon added. The modified materials obtained asdisclosed herein may be used in a variety of applications, such as thefabrication of clothing and various items of wearing apparel, socks,hosiery, footwear, shoes, home furnishing fabrics including upholsteryand window treatments including curtains and draperies, and fabrics foroutdoor furniture and equipment, as well as for industrial textile enduses.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a scheme showing the reaction of alkyl silanes with hydroxylgroups on a saccharide moiety.

FIG. 2 is a scheme showing the formation of the dialdehyde of a glucoseunit of cellulose, which is then reacted with an amine or hydrazide.

FIG. 3 is a scheme showing reaction of a glucose unit of cellulose withchloroacetic acid followed by coupling with an amine comprising ahydrophobic group.

FIG. 4 is a scheme showing the reaction of hydroxyls on cellulosematerials with bromides and epoxides.

FIG. 5 is a scheme showing the reaction of hydroxyls on a glucose moietyof cellulose with carbonyldiimidazole followed by reaction with anamine.

FIG. 6 is a scheme showing the reaction of hydroxyls on a glucose unitof cellulose with epichlorohydrin followed by reaction with an amine.

FIG. 7 is scheme showing crosslinking of hydroxyl groups on cellulosewith hydrophobically modified dimethyloldihydroxyethyleneurea.

FIG. 8 is a graph comparing the hydrolytic stability of palmitoylchloride treated cotton and a Scotchgarded® (3M, St. Paul, Minn.)material.

MODES FOR CARRYING OUT THE INVENTION

Methods and compounds for modifying materials, as well as modifiedmaterials produced by the methods are provided. In one embodiment,materials are modified by the attachment of hydrophobic groups. Usingthe methods disclosed herein, a variety of materials including textiles,such as cellulosic textile materials, including cotton fiber, as well asfibers of proteinaceous materials such as wool and silk, and syntheticfiber materials, such as nylon, and various man made materials such asregenerated cellulose or regenerated protein, are modified to impartselected properties on or to the material. Desirable properties that canbe imparted to the modified materials include water repellency,durability to dry cleaning and laundering, detergent-free washing,resistance to abrasion and soiling, grease resistance, increase strengthand enhanced comfort.

Materials

A variety of materials, including textile fibers, yarns and fabrics canbe modified as disclosed herein. The materials can be modified in oneembodiment by the covalent or noncovalent attachment of certain polymersand monomers to the material. In one embodiment, materials comprisingmodifiable functional groups may be modified, for example, by theattachment of hydrophobic groups. The modifiable functional groups inthe materials are, for example, capable of covalently reacting to attacha compound or polymer, for example, comprising a hydrophobic group tothe material. Exemplary modifiable functional groups include aminegroups, hydroxyl groups, thiol groups, and carboxylic acid groups. Themodifiable functional groups also can permit the modification bynon-covalent attachment of certain polymers or monomers, for example, byhydrogen bonding interactions, or hydrophobic interactions.

Exemplary materials that can be modified as disclosed herein includecarbohydrates, such as polysaccharides. Exemplary polysaccharidesinclude dextran, starch or cellulose. Other exemplary materials includeleather and natural textile fiber materials, such as wool or silk, aswell as fiber of synthetic polymers such as polyamines and polyamides,e.g., nylon, and proteinaceous materials, such as wool and silk. Manmade materials may be modified such as regenerated cellulose and viscoserayon, and regenerated proteins, and various cellulose acetates. Othersynthetic polymer materials also may be modified, such as polyesters,polyethers, polyacrylics, various modified acrylics, polyurethanes, andcombinations thereof with other monomers and polymers.

In one embodiment, materials comprising amino acids, for example in theform of poly(amino acids), may be modified. For example, in oneembodiment, wool and silk materials comprising proteins may be modifiedas disclosed herein.

Cellulosic Materials

In one embodiment, a variety of cellulose containing materials may bemodified as disclosed herein. Exemplary materials include textilefabrics for clothing and apparel, paper materials, such as filters, andother materials such as chromatography materials. For example, cottonfibers or cloth made of such fibers may be modified.

Cellulose containing materials are modified, for example, by thecovalent attachment of hydrophobic groups. The modification of cottonmaterial can improve properties of the cotton, such as its waterrepellent characteristics, or permanent press properties.Advantageously, the cotton containing materials may be modified afterprocedures such as dyeing of the cotton. The cotton material may be alsoprovided as a blend with other natural and/or synthetic materials,either before or after the modification step wherein, for example, thehydrophobic groups are covalently attached.

Cellulose is a mostly linear polymer of glucose units connected byβ-1,4-linkages as shown below:

Each strand of natural cellulose is from 2000 to 3000 glucose unitslong. The cellulose polymers are easily hydrolyzed by acid. Thecellulose molecules form fibrils in which the majority of the moleculesare oriented in the direction of the fiber axis, giving the fiber itsstrength. Between the crystalline regions are semicrystalline andamorphous areas. The configuration of the fiber is stabilized byhydrogen bonds and van der Waals forces.

In cellulose, each glucose unit contains three hydroxyl groups whichgives cellulose its hydrophilic characteristics. Using the methodsdisclosed herein, these hydroxyl groups may be chemically modified toalter its properties. For example, the hydroxyl groups may be modifiedwith hydrophobic groups, such as hydrocarbon and fluorocarbon groups, toimpart hydrophobic characteristics to the cellulose, and consequently,to materials, such as clothing made from the cotton.

Amino Acid Containing Materials

In one embodiment, materials comprising poly(amino acids), such asproteins, may be modified as disclosed herein. For example, wool or silkmaterials may be modified. Wool materials, for example, may comprise aprotein such as keratin, which may be modified as disclosed herein.

Materials comprising amino acids, for example, comprising proteins, maybe modified as disclosed herein, by modification of substituents on theamino acid side chains. For example, the hydroxyl on serine, threonine,or tyrosine may be modified. The side chain on lysine, arginine andhistidine may be modified. The carboxylic acid group on aspartate andglutamate may be modified. The amide group on asparagine and glutaminemay be modified, as well as the thiol group on cysteine. Modificationcan occur, for example, by the covalent or non-covalent attachment ofcompounds, including monomers and polymers, that alter properties of thematerial as disclosed herein.

Covalent Attachment of Hydrophobic Groups

A variety of materials with modifiable functional groups, such as amineand hydroxyl, may be modified as disclosed herein. While, in oneembodiment, the modification is described in detail herein with respectto cellulose by way of, example, other materials including hydroxyl orother modifiable groups may be modified by the methods disclosed herein.

Covalent Attachment of Acyl Groups Using a Hindered Base

In one embodiment, functional groups, such as hydroxyl groups, can bemodified by the covalent attachment of an acyl group. Hydroxyl groupshave been found to be fairly difficult to covalently modify andtherefore require reactive reagents to modify them. Methods of reactingreagents with hydroxyls have been developed in the art of chemistryincluding the use of acid chlorides, anhydrides, succinimides,carbonyldiimidazoles. These methods, however, are sensitive to water andtherefore water must be excluded from these reactions or excesses ofreactants can be used. Acid chlorides (and sometimes anhydrides) areadvantageous because they are readily available and do not require priordeprotonation of the target hydroxyls. However, the reaction of acidchlorides with hydroxyls produces HCl, which disadvantageously canhydrolyze or otherwise degrade the material. For example, the reactionof acid chlorides with cellulose can cause hydrolysis and degradation ofthe cellulose material, such as cotton or rayon containing fabric forapparel or upholstery.

In one embodiment, this problem is overcome by the use of a hinderedbase in the reaction of an activated acyl group, such as acyl chloride,with a modifiable functional group, such as a hydroxyl. An exemplaryreaction scheme, wherein an acid chloride is reacted with a hydroxylgroup on cellulose, in the presence of a hindered base, is shown inScheme I below:

The presence of the hindered base, such as tripentylamine,advantageously neutralizes the HCl produced in the reaction, andpromotes acylation without degradation of the treated material. Incontrast, relatively unhindered bases, such as pyridine andtriethylamine, do not give desirable results. While not being limited toany theory, it is possible that the improved results may be due tosteric hindrance of the pentyl groups or solubility of the base.

While the covalent attachment of hydrophobic groups using acid chloridesand anhydrides in the presence of a hindered base is disclosed herein indetail, other activated acyl groups may be used in the presence of thehindered base, as well as other methods of covalent attachment.

As used herein, the term “hindered base” refers to a base that iscapable of promoting an acylation reaction while minimizing degradationof the material being acylated. Preferred are hindered amine basesincluding three straight, or branched carbon chains, wherein each chainincludes at least three carbons.

In one embodiment, the hindered base has the formula:

R₁R₂R₃N

wherein R₁, R₂, and R₃ are independently a C3-C10 branched or straightchain saturated or unsaturated hydrocarbon. Preferably, R₁, R₂, and R₃are independently a C4-C8 straight chain saturated hydrocarbon. Forexample, in a preferred embodiment, the hindered base is tripentylamine,or tributylamine. Additionally the hindered amine may be a cyclic amine,such as 1,8-bis(dimethylamino)naphthalene, or N-methylaniline. Otherbases include 1,8-diazabicyclo [5.4.0.] undec-7-ene,N-methylmororpholine, and N-methylaminopyridine.

Reaction Conditions Using Hindered Bases

The reaction of the activated acyl group with the modifiable functionalgroups, such as a hydroxy, for example on cellulose, may be conducted,in one embodiment, by using a concentration of the hindered base whichis in excess of the concentration of the activated acyl group. Forexample, the reaction may be conducted neat or in an organic, preferablyanhydrous solvent, such as ether or methyl sulfoxide, dioxane,tetrahydrofuran or dimethylformamide. The temperature of the reactionmay be varied depending on the reagents and cellulose materials used.The temperature may be, for example, about 0° C. to 100° C., for exampleat room temperature (about 25° C.). After the reaction is complete, thecellulose may be optionally rinsed with an anhydrous organic solventsuch as ether and dried. Optionally, the activated acyl group may be agas, which is directly applied to the cellulose material, either in thepresence or absence of a solvent.

In one embodiment, cellulose is reacted with an acid chloride containinga hydrophobic acyl group, such as hexadecanoyl chloride. The reaction isconducted, for example, with a molar ratio of 1.5:1 of the hinderedbase, such as tripentylamine, to the acid chloride. Optionally thereaction is conducted in a solvent such, as ether. For example, areaction may be conducted with 0.1 g/ml cellulose, 1 M acyl chloride,and 1.5 M of the hindered base, such as tripentylamine, in a solventsuch as ether. The reaction may be conducted in one embodiment at roomtemperature for about 1-12 hours for activated acyl groups containinglonger hydrocarbon chains, such as those including greater than about 5carbons, such as hexadecanoyl chloride. In the embodiment wherein morereactive activated acyl groups are used, shorter reaction times, forexample 1 hour or less at room temperature may be used.

The cellulose material may be treated first with an activated acylgroup, including a hydrophobic moiety, in order to acylate hydroxylgroups on the cellulose with the acyl group containing the hydrophobicgroups. After the reaction is complete, the cellulose is reacted with ashort carbon chain activated acyl group, such as acetyl chloride, toacylate any remaining accessible free hydroxyl groups. The reaction timeat room temperature for the smaller acyl chlorides may be shorter, forexample about 1 hour.

In another embodiment, the cellulose may be reacted sequentially or atonce with different selected amounts of activated acyl groups, toprovide a mixture of hydrophobic acyl groups covalently attached to thecellulose.

Hydrophobic Groups

A variety of hydrophobic groups may be attached to materials asdescribed herein. As described above, in one embodiment, a materialcomprising a modifiable functional group, such as cellulose, is reactedwith one or more activated acyl groups in the presence of a hinderedbase. While cellulose is discussed herein by way of example, othermaterials, including other polysaccharides, may be modified as disclosedherein, as well as materials containing amines.

For example, the activated acyl group may be an acid chloride oranhydride. Exemplary compounds are shown in Scheme II below. Forexample, the activated acyl group may be an acid chloride, RCOCl oranhydride (RCO)₂O. Mixed anhydrides also may be used. The R group may beselected to determine the properties of the cellulose, after acylation.R in one embodiment is a cyclic or branched or straight chainhydrocarbon or fluorocarbon.

The activated acyl group may be an acyl chloride, RCOCl or anhydride(RCO)₂O, wherein R is a C5 to C20 saturated or unsaturated branchedcyclic or straight chain hydrocarbon, for example a straight chainC10-20 saturated hydrocarbon. The acid chloride may be, for example,hexadecanoyl chloride. For more hydrophobicity, longer chain lengths maybe used.

In another embodiment, polymeric molecules, e.g., polyethylene acidchloride, maleic acid or polypropylene maleic acid chloride may be used.Exemplary polymeric activated acyl groups which can be used are shown inFormulas 1, 2 and 3 below, wherein m, n, o and p are independently about10 to 10,000, e.g., about 100-10,000. The molecules of Formulas 2 and 3are multifunctional and can attach at multiple sites on the cellulose,and can form “loops” and “trains” respectively on the cellulose.

The activated acyl group also may be an acid chloride, R(CH₂)₂COCl oranhydride, (R(CH₂)₂CO)₂O, wherein R is a C1-C12 branched, cyclic orstraight chain fluorocarbon. For example, R may be CF₃—. In anotherembodiment, R can be CF₃(CF₂)_(n)— wherein n is, for example, 0 to 10(as shown in Formula 4 in Scheme II below). Fluorinated chains aregenerally more hydrophobic than hydrocarbon chains of the same length,so shorter chains may be used. For example, cellulose may be renderedhydrophobic by reaction with the activated hydrophobic acyl group,CF₃(CF₂)₂(CH₂)₂COCl. Mixtures of hydrocarbons and fluorocarbons can beused.

Exemplary acid chlorides or anhydrides which may be used to treat amaterials such as cellulose or other carbohydrate material in thepresence of a hindered base are shown in Scheme II below.

The methods disclosed herein are advantageous, because in the presenceof the hindered base materials, such as cellulose materials, includingcotton, may be covalently modified with hydrophobic groups, withoutdegradation of the cellulose. Thus, certain properties of the cellulosematerial, such as permanent press properties and stain resistance can beenhanced.

In another embodiment of the invention, the hydrophobicity of themodified material such as cellulose can be enhanced by a second reactionof the modified cellulose with a smaller hydrophobic molecule, such asacetyl chloride after the initial reaction. The smaller hydrophobicmolecules can react, with any unreacted hydroxyl groups that the longerchain acid chlorides could not access, for example, for steric reasons.Different ratios of acyl groups may be selected and attached to provideselected hydrophobicity properties of the material such as cellulose.

Processes Using Hindered Base Method

Materials, such as wool or cellulose materials, such as cotton, may betreated as disclosed herein before or after treatment of the materialwith other reagents such as dyes. Thus, for example, material, such ascotton or wool may be processed by treatment with dyes, cutting, and/orprocessing into articles such as clothing, and the material may behydrophobically modified at any stage of the process.

An exemplary process is shown below in Scheme III for the solution phasetreatment of cotton with a long chain acyl chloride (Acyl ChlorideR_(L)), such as hexadecanoyl chloride, and then reacting unreactedhydroxyl groups with a shorter chain acyl chloride (Acyl ChlorideR_(S)), such as acetyl chloride, in the presence of a hindered base,such as tripentylamine. After the reaction, the hindered base can beregenerated by treatment with a strong base.

Other Methods of Covalent Attachment of Hydrophobic Groups

Other methods may be used to attach hydrophobic groups to materials suchas cellulose and wool.

Modifiable functional groups on materials, such as cellulose and wool,also may be modified by reaction with alkyl silanes. For example, freehydroxyls on materials such as cellulose or wool may be reacted withalkyl silanes.

The alkylsilanes may be, for example, chlorosilanes, methoxysilanes orethoxysilanes. Exemplary chlorosilanes include RSiCl₃, RSi(Me)Cl₂, andRSi(Me)₂Cl, wherein R is alkyl, for example a straight chain, branchedor cyclic hydrocarbon, such as hexadecyltrichlorosilane, or haloalkyl,such as fluoroalkyl, for example, a straight chain, branched or cyclicfluorocarbon, such as(heptadecafluoro-1,1,2,2,-tetrahydrodecyl)trichlorosilane.

Exemplary ethoxysilanes include RSi(OEt)₃, RSi(Me)(OEt)₂, andRSi(Me)₂OEt, wherein R is alkyl, for example a straight chain, branchedor cyclic hydrocarbon, such as hexadecyltriethoxysilane, or haloalkyl,such as fluoroalkyl, for example, a straight chain, branched or cyclicfluorocarbon, such as(heptadecafluoro-1,1,2,2,-tetrahydro-decyl)triethoxysilane.

An example is shown in FIG. 1, wherein a glucose moiety of cellulose ismodified by the attachment of an alkylsilane. In FIG. 1, R is ahydrocarbon or fluorocarbon moiety, such as hexadecyl- orheptadecafluoro-1,1,2,2-tetrahydrodecyl. In FIG. 1, R—SiX₁X₂X₃ is analkyl silane, such as a chlorosilane, methoxysilane or ethoxysilane,wherein one or more of X₁, X₂ and X₃, is, for example, chloro, ethoxy ormethoxy, and the remainder of X₁, X₂ and X₃ are, for example, methyl;and R′ is OH or OSi(OH)₂R.

Materials including a saccharide moiety, such as a glucose moiety, oneor more saccharide units may be oxidized, for example using aqueoussodium periodate, to form a reactive dialdehyde. The dialdehyde, forexample, may be reacted with a hydrazide to form hydrazone linkages, orwith an amine in the presence of a reducing agent, such as sodiumcyanoborohydrate. An exemplary scheme of the formation of the dialdehydeof a glucose unit of cellulose is shown in FIG. 2. In FIG. 2, R is ahydrophobic group, such as a hydrocarbon or fluorocarbon.

Modifiable groups on materials may be activated with chloroacetic acidand then coupled to a compound such as an amine comprising a hydrophobicgroup. An exemplary scheme of the formation of the chloroacetic acidderivative of a glucose unit of cellulose by treatment with chloroaceticacid in alkaline buffer, followed by coupling with an amine is shown inFIG. 3. In FIG. 3, R′ is a hydrophobic group, such as a hydrocarbon orfluorocarbon group. An exemplary coupling agent that can be used is EDC(1-ethyl-3-(3-dimethylaminbpropyl)carbodiimide). In FIG. 3, in theproduct, chloroacetic acid may attach in the reaction to any one or moreof the free hydroxyls of the glucose unit. In the possible product shownin FIG. 3, R is OH or OCH₂CONHR′.

Modifiable functional groups on materials, such as hydroxyls oncellulose materials, may be reacted with bromides and epoxides, forexample in aqueous sodium hydroxide. An example of the reaction ofhydroxyls on a glucose moiety of cellulose is shown in FIG. 4. In FIG.4, R is, for example, a hydrophobic group, such as a hydrocarbon orfluorocarbon group.

Modifiable functional groups on materials, such as hydroxyls oncellulose materials, may be activated, for example, withcarbonyldiimidazole (CDI). An example of the reaction of hydroxyls on aglucose moiety of cellulose with CDI followed by reaction with an amineis shown in FIG. 5. Any one or more of the hydroxyls of the glucose unitmay react in the reaction. In the possible product shown in FIG. 5, ORis OH or OCONHR′. In FIG. 5, R′ is, for example, a hydrophobic group,such as a hydrocarbon or fluorocarbon group.

In another embodiment, modifiable functional groups on materials, suchas hydroxyls on one or more glucose units of cellulose can be activatedby reaction with epichlorohydrin followed by reaction with an amine, asshown in FIG. 6. Any one or more of the hydroxyls of the glucose unitmay react in the reaction. In the possible products shown in FIG. 6, ORis OH or OCH₂CHOHCH₂NHR′. In FIG. 6, R′ is, for example, a hydrophobicgroup, such as a hydrocarbon or fluorocarbon group.

Other Covalent Modifications

Halogenation

Soil resistant materials, such as cotton and wool fabrics, or anymaterial comprising C—H bonds, can be synthesized in one embodimentthrough a surface halogenation reaction, such as a fluorinationreaction, converting the carbon-hydrogen bonds at the surface tocarbon-fluorine bonds. A method of modifying a material, such as acellulose material is provided, comprising exposing the material to ahalogenating agent, such as fluorine gas, in an effective amount tofluorinate at least a portion of the material. This may be accomplishedby exposing a surface to 5 to 10% fluorine gas diluted in nitrogen atroom temperature for 1 to 15 min. Fluorine can penetrate below thesurface to a depth of 30 to 800 Å and this reaction can be performed ona large scale e.g., surface fluorinated polyethylene gloves are made bythis process as well as fluorinated polypropylene automobile fuel tanks.H. R. Allcock and F. W. Lampe, Contemporary Polymer Chemistry, PrenticeHall, Inc., Englewood Cliffs, N.J., 1990, p. 158.

Crosslinking

Cotton tends to wrinkle and shrink upon washing due to rearrangements ofthe cellulose chains within the fibers facilitated by water. Cotton iscomposed of both crystalline and amorphous regions of cellulose. Thecrystalline regions are very stable and resist wrinkling and shrinking,whereas water can penetrate the amorphous regions and facilitate chainslippage. R. M. Rowell and R. A. Young, Eds., Modified Cellulosics,Academic Press, NY, 1978. Therefore, the amorphous regions of celluloseare the source of the undesired properties of cotton. The amorphousregions may be made more rigid, so that the fabric is made both wrinkleand shrink resistant while maintaining the beneficial properties ofcotton.

In one embodiment, functionalized glucose molecules, including a glucosemolecule comprising a reactive functional group, such as anisothiocyanate, isocyanate, acyl azide, sulfonyl chloride, aldehyde,glyoxal, oxirane, carbonated imidoester, carbodiimide, succinimideester, epoxide, alkyl halide, anhydride, acid chloride, and activatedester are provided. Exemplary functional groups are disclosed in G. T.Hermanson, Bioconjugate Techniques, Academic Press, San Diego, Calif.,1996, pp. 137-165, the disclosure of which is incorporated herein. Allof these functional groups are reactive towards the hydroxyls ofcellulose. The functionalized glucose molecules are used to crosslinkthe amorphous regions of the cotton to produce an overall stable fiberresistant to wrinkling and shrinking. Due to the chemically accessiblenature of the amorphous region, functionalized glucose can penetratemore, readily into these regions and react to prevent conformationalchanges. Alternatively, a carbohydrate forming enzyme, such as glycogensynthase, starch synthase, dextran synthase, or cellulose synthase, asdescribed in L. Stryer, Biochemistry, W. H. Freeman and Co., New York,1988, p. 456, the disclosure of which is incorporated herein, can beused to link pure glucose to the cellulose fibers. The advantage of thisapproach is that the product is almost identical to crystallinecellulose, thus retaining all of the beneficial characteristics ofnatural cotton while imparting wrinkle and shrink resistance.

Modifiable functional groups on materials, such as hydroxyl groups oncellulose, also may be crosslinked with hydrophobically modifieddimethyloldihydroxyethyleneurea, as shown in FIG. 7, where R is ahydrophobic group, such as a fluorocarbon or a hydrocarbon.

Covalent Attachment of Enzymes

Reduction or elimination of detergents for fabric washing can benefitthe environment by reducing this source of water pollution. Soapmanufacturers often include enzymes with their surfactants to increasethe soil release properties of their detergents. Shimomura et al.,Textile Res. J., 67:348-353(1997). During the wash cycle, the enzymescatalytically hydrolyze and release proteinaceous soils adsorbed to thefabric. The disadvantage of this technique is that the enzyme is rinsedaway after the wash.

Provided are detergent free wash materials formed by methods whereinenzymes are covalently linked directly to materials such as cellulosematerials, such as cotton fabric, thus eliminating the need for use ofenzyme in the wash solution and possibly lowering or eliminating theneed for detergents. Preferably, the treated garment is simply soaked inwater to allow the surface-bound enzymes to hydrolyze and release soils.Methods for the attachment of enzymes to materials described in the artmay be used, for example, as described in G. T. Hermanson, BioconjugateTechniques, Academic Press, San Diego, Calif., 1996, pp. 630-639.Additionally, hydrocarbon or fluorocarbon chains may be attached to thefabric to give soil release properties. Exemplary enzymes includetrypsin, chymotrypsin and papain.

Applications

Covalent Attachment of Hydrophobic Groups to Impart Water Repellency

Water repellency is imparted by lowering the surface energy of thematerial, such as cotton fabric, below the surface tension of water,thus causing water to bead on the fabric. The formation of waterrepellent coatings is particularly useful for the production of waterrepellent outerwear, such as cotton or wool outerwear. The cotton orwool advantageously retains its breathability, flexibility and softnessafter modification. The hydrophobically modified material, such ascotton is useful in that it can be made in vibrant and varied colors andpatterns, and is light weight, and comfortable. Cotton also isadvantageous in that it is natural and inexpensive. Cotton and woolmaterials may be easily mass produced inexpensively and in a variety ofcolors, patterns and shades, with good and permanent water repellency.

Water repellent characteristics are imparted on materials, such ascotton-containing materials by chemically linking hydrophobic moleculesdirectly to the material such as cotton fibers. An advantage of thisapproach over prior coating or laminating processes used for cotton isthe use of a natural, inexpensive, and readily available cotton infiber, yarn or fabric form. This approach may be implemented quickly andcheaply using equipment present in textile mills, such as through a paddry cure process.

Cotton is composed mainly of the carbohydrate cellulose. It containsmany hydrophilic hydroxyl groups imparting it with high wettability. Todecrease its wetting properties, these hydroxyls are converted intohydrophobic groups. The attachment of hydrophobic moieties to the cottonis accomplished by covalently attaching a hydrophobic group to thehydroxyl moieties of cotton by methods disclosed herein, such as usingan acyl chloride (e.g., palmitoyl chloride) in the presence of ahindered base (e.g., tripentylamine) at room temperature, as describedin detail herein. The presence of the hindered base prevents unwantedhydrolysis of the cellulosic material by acids such as HCl producedduring the reaction without interfering with the reactivity of the acylchloride molecule and also catalyzes the reaction of hydroxyl with theacyl chloride. Optionally, a second step is conducted, wherein hydroxylsinaccessible to the larger acyl chloride are capped with a smallerorganic acid chloride (e.g., acetyl chloride) in a process referred toherein as backfilling. Monomeric hydrophobic molecules can readilypenetrate within the fabric to improve the durability of the coating.Similarly, the methods may be used for other materials includingmodifiable, functional groups, such as wool.

Covalent Attachment of Hydrophobic Groups to Impart Grease Repellency

Grease repellency properties may be imparted on a material, such ascotton or wool, using methods similar to that for producing waterrepellent fabric. In, grease repellent materials, the surface energy ofthe materials must be reduced below that of grease. Typically, grease isa hydrocarbon having a surface tension, similar to that of a hydrocarboncoating. Fluorocarbons are among the lowest surface energy substancesknown. Bain et al., J. Am. Chem. Soc., 111:7155 (1989). When attached tomaterials such as fabric, fluorocarbons will sufficiently lower theenergy of the fabric to produce grease and water repellency.

Methods disclosed herein for covalent attachment of hydrophobic groupsto materials may be used. In one embodiment, a partially fluorinatedacid chloride is reacted with a material, such as cotton fabric, in thepresence of a hindered base, such as tripentylamine, to produce greaserepellent fabric. The cotton further is backfilled with a smallerpartially fluorinated acid chloride, such as 2H,2H-trifluoropropanoylchloride, to achieve maximum repellency. With partially fluorinatedcompounds, such as dihydro compounds, the problems of completelyfluorinated compounds, which do not form durable finishes due to theactivation of the surface bond by the fluorine atoms close to thesurface resulting in instability to hydrolysis, are avoided.

Increasing the abrasion resistance of fabric can dramatically increaseits useful lifetime. Materials, such as cellulose materials, may becoated by covalent attachment of low surface energy monomers orpolymers, such as fluorocarbons, and high performance engineeredpolymers such as nylon and polyamides, to reduce friction, as disclosedherein. This coating thus protects the garment from wear and increasesits durability characteristics.

Covalent Attachment of Hydrophobic Groups to Impart Permanent PressProperties

When cotton fabric is immersed in water or heated, the weak forces(hydrogen bonds and van der Waals attractions) that hold the cellulosechains in place break and the chains become free to move. Upon drying orcooling, the chains freeze into whatever position they happen to be in.This physical process is known as wrinkling. Cotton materials may bemodified to improve their permanent press properties, with minimal lossof performance properties such as strength and abrasion resistance. Woolcan wrinkle in a similar matter.

In one embodiment, materials comprising modifiable functional groups,such as cotton or wool materials are reacted with polymeric acylchlorides, such as polyethylene acyl chloride or polypropylene acylchloride, as disclosed herein, to attach hydrophobic groups to theglucose units of the cellulose, or to amino acids in the wool, to endowthe modified fabric's surface with a synthetic quality. This type ofhybrid fabric can enhance the permanent press character, while retainingmany attributes associated with the original natural fibers, such ascotton or wool. The extent of chemical modification will determine thedurability of permanent press. Longer reaction times under strongerconditions with activated chemicals will lead to higher degrees ofchemical modification, and extent of polymer grafting onto the cottonsurface, and thus increased synthetic character.

Other Applications

A variety of materials can be modified as disclosed herein, includingvarious textile fiber materials, in a variety of forms such as fabric,yarn, and thread or as finished articles of apparel or home furnishingfabrics. The modified materials, such as cellulose cotton materials, orcotton containing materials, as well as wool, produced as describedherein may be used to form a variety of articles. For example, a varietyof clothing items, may be produced using the cellulose cotton materials,including shirts, pants, bathing suits, jackets and shoes. A variety ofarticles of furniture may be produced including outdoor furniture orfurniture coverings. Other items include furniture upholstery, curtains,and bedding items, such as bedsheets or bedspreads, carpets, as well aspillows or pillow coverings, area rugs, throw rugs and mats of varioustypes. Articles for outdoor use may be produced including car upholsteryand panels or furniture coverings, air filters such as automobile airfilters, tents, umbrellas, land, beach, equipment.

A variety of surfaces can be modified using the methods disclosedherein, to improve their hydrophobicity, including the surface ofcellulose containing, materials including cloth and filters.Additionally the surface of paper or wood, including wood furniture, canbe treated as disclosed herein.

The invention will be further understood by the following non-limitingexamples.

EXAMPLES Example 1

Blue dyed Levi's™ denim cotton fabric was added at a concentration of0.1 g/ml to a solution of hexadecanoyl chloride (1M) and tripentylamine(1.5M) in anhydrous ethyl ether. The ether, tripentylamine andhexadecanoyl chloride were obtained from Aldrich Chemical Co., St. LouisMo. The solution was either inverted or stirred at room temperatureovernight. Acetyl chloride, then was added to 0.3 M and reacted for 6hours. After the reaction was complete, the cotton was rinsed withdiethyl ether, and dried.

The covalent attachment of the long chain hydrocarbon imparted ishydrophobic character to the cotton, as evidenced by water beading onthe surface, when soaked overnight in a ≧1M solution in ethyl ether.

Example 2

The hydrolytic stability of hydrophobic tails (palmitoyl chloride)grafted through ester bonds on cotton was tested. A cotton swatch (TestFabrics, West Pittston, Pa.) was treated as described in Example 1.Subsequently, the material was placed in a boiling detergent (Tide)solution (20 g/L) under vigorous agitation. The boiling temperature ofthe solution was approximately 100° C. Mechanical agitation wasimplemented using a stirrer with speed set at the highest setting.Additionally, a sample of fluorocarbon treated, Scotchgarded® materialwas agitated in the boiling detergent solution. The Scotchgarded®material quickly lost all its water repellency under the vigorouswashing conditions. In contrast, the palmitoyl chloride treated sampleshowed robust and persistent water repellency. FIG. 8 is a graph ofsurface tension vs. time comparing the hydrolytic stability of thepalmitoyl chloride treated cotton and a Scotchgarded® material after theboiling detergent treatment.

The surface tension of unmodified cotton was 72 mN/m. The surfacetension of cotton treated with pentylamine and palmitoyl chloride was 32mN/m, and the surface tension of cotton treated with palmitoyl chloride,acetyl chloride and tripentylamine was 30 mN/m. Addition of acetylchloride slightly improved hydrophobicity of the sample by filling inspaces that the palmitoyl chloride could not access for example due tosteric effects.

What is claimed is:
 1. A method of modifying a textile material toincrease the hydrophobicity of the material, the method comprisingcrosslinking the material with hydrophobically-modifieddimethyloldihydroxyethyleneurea, the hydrophobically-modifieddimethyloldihydroxyethyleneurea comprising a covalently attachedfluorocarbon group.
 2. A method according to claim 1 wherein the textilematerial is a carbohydrate-containing material.
 3. A method according toclaim 1 wherein the hydrophobically-modifieddimethyloldihydroxyethyleneurea has the following formula, where R is astraight chain, branched or cyclic fluorocarbon:


4. A method of modifying a cellulose-containing textile material toincrease the hydrophobicity of the material, the method comprisingcrosslinking hydroxyl groups on the material with hydrophobicallymodified dimethyloldihydroxyethyleneurea, the hydrophobically modified dimethyloldihydroxyethyleneurea comprising a covalently attachedfluorocarbon group.
 5. A method according to claim 4 wherein thehydrophobically-modified dimethyloldihydroxyethyleneurea has thefollowing formula, where R is a straight chain, branched or cyclicfluorocarbon:


6. A modified carbohydrate-containing textile material produced byreacting the material with hydrophobically-modifieddimethyloldihydroxyethyleneurea comprising a covalently attachedfluorocarbon group, thereby to crosslink hydroxyl groups on the materialwith the dimethyloldihydroxyethyleneurea, the modified textile materialexhibiting increased hydrophobicity.
 7. A modified textile materialaccording to claim 6, wherein the hydrophobically-modifieddimethyloldihydroxyethyleneurea has the following formula, where R is astraight chain, branched or cyclic hydrocarbon or a straight chain,branched or cyclic fluorocarbon: